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Lifting Latent Fingerprints from Difficult Surfaces

Written by Gary Gulick

ALMOST ANYONE can find, process, and lift a latent print that happens to be in a logical and obvious place like a door handle, a beer can, or a butcher knife. But sometimes, a latent print is not just sitting there in a logical and obvious place. Sometimes, you have to use your imagination to find the print and your skills to lift it.

“A lot of times, it is our own attitude that defeats us,” said Daryl Clemens, a crime-scene technician with the Forensic Services Unit of the Grand Rapids (Michigan) Police Department. “We don’t look, so we don’t find anything. Other times, a person will just look at an unusual object and say ‘I can’t get fingerprints from that!’ And they don’t even try to do anything with it.”

Clemens went on to tell about a class he was teaching a few years ago when one of the students’ assignments was to lift latent prints from a golfball. Most thought the assignment was impossible because of the dimpled natured of the golfball’s surface. And when they succeeded, they were amazed. “One guy just happened to be working a case that involved golfballs,” Clemens said. “It seems somebody had stolen golfballs from a golf course and had then used a slingshot to take out a bunch of car windows. He was very happy to learn how to get prints from that surface.”

Different cures for the closed-mind syndrome

Experts like Clemens who teach classes in latent-fingerprint recovery techniques will agree that a closed mind or inactive imagination are often a technician’s main obstacle. Michael Stapleton is one of those experts. He recently retired from the Federal Bureau of Investiga-tion (FBI) after 34 years to start his own company, Forensics R Us. His approach to overcoming the notorious closed-mind syndrome is quite simple:

“I will ask students to bring something really unusual that they think might be challenging for latent-print recovery,” said Stapleton.

“One officer found a feather outside on the ground and brought it in to class. He placed his own print there to see if it could be developed—and he was surprised when we succeeded.” (See the photo at the top of this page.) Stapleton described some other unusual surfaces that had been processed by his students, including lemons, bananas, and tree leaves.

Clemens had some similar stories about finding and lifting prints from strange or difficult places.

“We made a burglar with latent prints from a fork,” Clemens recalled. “We found his prints on both ends of the fork: the handle and the tines. Why did we even try? Well, mainly because the homeowner told us the burglar must have helped himself to some lunch while he was in the house. So I threw some dust on it—and there was a print.”

Other strange recoveries for Clemens include the trigger on a pump-spray bottle. “A guy was cleaning up blood at his crime scene with the cleanser in the spray bottle. We found his prints on that tiny, curved trigger on the bottle.”

But one of the trickiest examples in Clemens’ experience involved the time they recovered a print from the inside of an automobile’s dashboard. “They had stolen a car stereo and in doing so, they had to peel back the dashboard to get to it. We got latent prints that were on the plastic on the inside of the dashboard.”

Firearms are perhaps among the most difficult objects to yield good latent fingerprints. According to Clemens, technicians will typically get prints on only about ten percent of the guns that are inspected.

“Why are guns so difficult? There are a number of factors involved,” said Clemens. “One of them has to do with the textured nature of the area where the gun is being held. That area is not good for prints. Another factor has to do with how the firearm was treated before the crime. If the person took good care of it, then it probably has oil on it—which makes it almost impossible to get a good print. And if they have not taken care of it, the surface might be rusty—and rust is not good for lifting prints.”

Always be alert for the latest technology

Many agencies have a protocol that calls for fuming almost all guns with superglue (cyanoacrylate). “When I was still with the FBI,” recalled Stapleton, “super-glue was one of our best developers for fingerprints. In one case, we were able to develop a fingerprint with superglue seven years after the crime. That just goes to prove that latent fingerprints can last a long time!”

Unfortunately, a lot of departments are pressured by time constraints, said Stapleton. “They want their people to get in there and get out. But in the FBI, we were always able to take our time.”

Stapleton cited a 1993 case as an example. In 1993, the FBI was helping with a case where a 12-year-old girl—Polly Klaas—was kidnapped from her bedroom at 10:30 at night.

“The Petaluma Police Department had been in that bedroom before we got there and they had dusted everything with black fingerprint powder. But none of the prints led them to the kidnapper. We decided to try something new and unusual that most departments did not have back then: an alternate light source (ALS). Our team used Redwop fluorescent powder and the forensic ALS to go over the bedroom. And that system was the only one that revealed the friction-ridge impression that came back to the kidnapper, Richard Allen Davis.”

What can crime-scene teams across the country learn from this?

“It is basically a matter of trying all of the tools at your disposal to see if you can get the fingerprint,” said Stapleton. “The FBI’s IAFIS (Integrated Automated Fingerprint Identification System) is a great tool. If you can get a latent-print impression from the crime scene, then you stand a very good chance of match-ing it with someone in the system.”

These photos illustrate that evidence found after a fire can still bear latent fingerprints that can be developed by gently brushing the soot off of the object. The result is shown below. No fingerprint powder was used.

If possible, you should always stay current with the latest products and techniques. Here are observations about various tools:

Superglue fuming

As you already know, there are advantages and disadvantages to almost everything in this world. For example:

One of the advantages of superglue fuming is that you can fume a piece of evidence and still send it to the laboratory for DNA testing. (Several studies show that testing for DNA actually goes better after the fuming.) Superglue fuming is also effective on items that have been outside or are wet, like beer bottles or broken window glass. Here are some of the disadvantages: If you fume evidence too long, you will probably end up with a chalky mess. Also, this technique will not work on porous items (try ninhydrin, instead). And the item you are going to fume is limited to the overall size of your fuming tank.

Magnetic powder

Most experts consider magnetic powder to be a little bit more sensitive and that it tends to work better on some of the harder surfaces. It will not work well, however, on any surface that is wet or even slightly magnetized.

RUVIS

This acronym stands for reflected ultra-violet imaging system. The comments about this system from Clemens were mostly positive (“It is very effective at finding prints you would have missed otherwise”), although he also had some cautionary comments about its use (“It is expensive—and it is somewhat time-consuming because you have to process the whole room, photograph your findings, and then come back and do the actual lifting.”)

ALS

Most forensic experts will agree that the alternate light sources (ALS) are remarkably effective in helping you find latent prints and biological fluids. They are expensive, however. And some of the experts suggest that certain small, light-emitting diode (LED) devices can be used for the same purpose. They are not as bright as the larger ALS units, of course. But they are cheaper.

The photo to the right shows latent fingerprints that were developed with an orange fluorescent powder. An orange filter was then placed on the camera lens to block out blue light, thereby enhancing the detail in the fingerprint image.

Polyvinyl-siloxane

For many technicians, the gel products known as Accutrans and Forensic Sil are among their top choices for lifting prints from difficult surfaces. First, you dust the print and then apply the gel. It only takes about five minutes to dry—and when you pull it off, you have the powdered impression. Stapleton said they had even recovered a print from a tree leaf using Forensic Sil. The same individuals who find these products to be their favorites do caution that the product is expensive—and they recommend taking care to cap the tube so the gel does not harden.

The photo below shows how latent fingerprints can be developed on the adhesive side of tape with products designed for this application. In this case, the prints were de-veloped on the adhesive side of electrical tape. The non-sticky side can also yield latent fingerprints with the use of superglue.

Some final thoughts about finding difficult prints:

Clemens had some straightforward advice to anyone in law enforcement who is involved with finding prints at crime scenes.

“You must practice,” said Clemens. “And the time to practice is not when you are out on a major event. The time to practice is when you are on a minor call or when you can work on some test samples that you’ve made up.

“But there are basically two real keys to success in working hard-to-find latent fingerprints. Number One: Have an open mind. And Number Two: Put powder on a variety of things to see what you can find.”

The bottom line is simple:

You will never know if something has prints on it until you have tried everything to find them. To say that you have absolutely no chance of finding prints is the wrong attitude. And that attitude that will be reflected by the number of latent fingerprints you can collect at the crime scene.

ORIGINALLY PUBLISHED:
"Can You Find It?" written by Gary Gulick
May-June 2008 (Volume 6, Number 3)Evidence Technology MagazineBuy Back Issue